Compact modeling of short-channel effects in back-gated 2D Negative Capacitance (NC) FETs

Abstract

The negative capacitance field-effect transistor with 2D channel material (2D NC-FET) holds significant promise for low-power applications owing to its remarkable resilience against short-channel effects (SCEs) and favorable noise characteristics. In this study, we establish a compact current-voltage (I-V) model for short-channel back-gated 2D NC-FETs with metal-ferroelectric-metal-insulator-semiconductor (MFMIS) structure by self-consistently solving the two-dimensional Poisson, drift-diffusion and Landau-Khalatnikov equations. The proposed model is valid and continuous throughout the entire operating regime, including the fully-depleted region, partly-depleted region, and accumulation region. Furthermore, we derive analytical equations for the threshold voltage (V_TH) and subthreshold swing (SS) of back-gated 2D NC-FETs based on the developed I-V model. Lastly, we elucidate the influence mechanisms of various device parameters and voltage bias on the subthreshold characteristics of short-channel back-gated 2D NC-FETs using the proposed I-V model in conjunction with analytical expressions of V_TH and SS. Our findings reveal that back-gated 2D NC-FETs shows unconventional degradation behavior in V_TH and SS, resulting from the competition between traditional short-channel effects (SCEs) and novel negative capacitance (NC) effects.